Paging systems are known whereby a centrally located operator can call up a person by name over a tannoy system.
Radio paging systems are also known whereby in a similar manner, but with greater secrecy, each one of a group of people carrying individual radio receivers can be called up using a radio transmitter to transmit an appropriate call up signal to cause the appropriate one of the radio receivers to emit a signal (either audible or visual or both) to thereby alert the carrier to make contact with the central operator.
Both systems rely on a telephone system within the environment within which the called up people are located to enable the paged person to make contact with the central operator.
Neither system however enables the operator to determine in advance whether any particular carrier is actually within the environment and where, in the environment, the carrier is actually located at any particular time. In each case the operator only becomes aware of whether the carrier is within the environment let alone where the carrier is located, after the carrier has made contact with the operator by establishing a telephone link using a locally situated telephone receiver.
It is one object of the present invention to provide a system by which a central controller (which may be a person or programmed computer), can rapidly determine whether a particular carrier is located within a given environment and if so where the carrier is located within the environment, to thereby enable the controller to make contact with the carrier by using a standard internal telephone system to cause a telephone near to where the carrier is located to ring. In this way the controller can route an incoming telephone call from another person (who may be within the environment or calling in from outside, as for example by using the public telephone network), directly to a telephone convenient to where the carrier is actually located at the time the call is received.
It is a further object of the present invention to provide a system by which a centrally located controller (which may be a person or programmed computer or the like) can grant or deny access to a carrier to a restricted region of a predetermined environment.
It is a subsidiary object of the invention to provide a system to record the occasions where the carrier gains access to some or all of selected regions within an environment.